Potting soil is typically a combination of dirt, fertiliser, organic matter, vermiculite and perlite. These substances may be excellent for encouraging the growth of plants, but they can create nasty stains on your carpet. If you accidentally get potting soil on your carpet, don't despair. Potting soil stains can often be removed from carpet using the right procedures and tools, and if you treat the stain fairly quickly after it occurs.
Allow the potting soil to dry completely if it is moist.
Vacuum the area to remove dirt and debris.
Fill a container with 2 cups of warm water and add one squirt of dish soap to the water.
Dip a white cloth into the soapy water and use it to sponge the area. Dab the area. Do not rub.
Blot the area dry with a clean, dry cloth.
Repeat dabbing the area with soapy water and blotting it dry until the stain is removed.
Dab the area with a little cold water (with no soap added) and blot dry.